A fuel cell generates electrical energy using movement of electronics that are generated during oxidation and reduction reactions of reactants. In these reactions, ions generated from the reactants move between each of the electrodes through an electrolyte membrane and electrons generated by a chemical reaction of the reactants move through the electrode provided at each reactant side. In order to increase a reaction rate of gas that becomes the reactants, a gas diffusion layer (GDL) is provided on outer surfaces of the each electrode.
The electrolyte membrane and each electrode are surface-attached to each other to easily move the ions, which is a membrane electrode assembly (MEA). The membrane electrode assembly has a thin thickness and low rigidity. Therefore, the membrane electrode assembly may be easily deformed or damaged during the bonding process and thus has a high defective rate, and may be easily deformed and damaged even upon handling.
Therefore, a reaction layer in which the membrane electrode assembly and the gas diffusion layer are integrated is manufactured by injection-molding an integrated frame by stacking the membrane electrode assembly and the gas diffusion layer and using a resin, etc., on an outer circumferential surface thereof, such that the handling easiness of the membrane electrode assembly may be improved.
Bipolar plates are stacked on an upper surface and a lower surface of the reaction layer to form the fuel cells and the cells are stacked to form a fuel cell stack. In the fuel cell stack, a reaction space is formed between the reaction layer and the bipolar plate to make reaction gases flow and a cooling space is formed between the bipolar plates to allow cooling water flow.
In the fuel cell using hydrogen and oxygen as the reaction gases, if each of the reaction gases reacts to each other, water is generated as the resultants. In the reaction layer, the electrolyte membrane requires a predetermined level of moisture to move the reaction ion. However, if the amount of water generated by the reaction of hydrogen with oxygen increases, the electrolyte membrane covers a surface of the reaction layer to prevent the reaction gases from being contacted with the reaction layer, and thereby, the reaction does not occur.
As described above, a phenomenon, in which water is the reactants within each of the fuel cells and is excessive and thus the chemical reaction due to the reaction gases is suddenly reduced, is called a flooding phenomenon. To prevent the above phenomenon, it is necessary to remove the water generated in each of the fuel cells when operating the fuel cell.
The contents described as the related art have been provided only for assisting in the understanding for the background of the present disclosure and should not be considered as corresponding to the related art known to those skilled in the art.